HBO was recently a victim of massive cyberattack, joining the likes of Yahoo & Sony Pictures who have all been attacked by hackers in the past. Now THR reports that FBI (Federal Bureau of Investigation) has joined into the investigation, which is clearly a not good sign for the network.

During the Sony hack, cybercriminals released about 200 GB of sensitive data which resulted in expulsion of co-chair Amy Pascal. The attack on HBO could be a lot worse as hackers have claimed to have stolen around 1.5 TB of data, over 7 times that of Sony’s. Former Secret Service agent and cybersecurity expert Erik Rasmussen tells THR:

“At 1.5 terabytes, it could be a whole block of TV, or worse, it could be emails, financial documents, employee or customer information. The fact that you have law enforcement (FBI) and a [cybersecurity] firm (Mandiant) involved most likely means this will be a very large incident for HBO.”

As of now, episodes of Room 104 and Ballers as well as 2 episodes of Barry have leaked online. Also, a low quality version episode 4 (The Spoils of War) of Game of Thrones season 7 has made its way to piracy websites but HBO says that it is unrelated to the hack and was leaked through a distribution partner. Hackers have also promised that more content is on its way soon and according to Variety, they will release more data this Sunday at 12 GMT, same day as the new episode of Game of Thrones. Could this mean that they have a full epsiode for release? We’ll have to wait until Sunday to find out.